The big problem with these is the fact that fumbles become MORE likely as you increase in level. (not to mention the extra die rolling). For example:
1st level Joe has a 1 in 20 (5%) chance of rolling a natural 1. That means when he charges that orc coming into his farm he has a 5% chance of messing up bad.
Now let's look at Turgoth the Amazing, whom is a 20th level fighter and has four attacks in a round. He charges the Dragon of Doom and only has a 81.45% chance of NOT ROLLING a ONE. That's almost a 14% better chance of messing up then ol Joe.
If you throw in two weapon fighting and have six attacks, you have nearly a 1 in 4 chance of a critical fumble EVERY ROUND?!
Now. Obviously you could make a "fumble check" or some such every time you roll a one based on your level to kind of circumvent this silliness. But this involves 1) more die rolls, 2) the higher level people still have to check more often.
Now, despite these problems, I would like to see a neat system put into place. Anyone got anything?
Perhaps you'd need to roll a number of ones in a round based on your level or BAB? Of course this would make the chances of a fumble miniscule very quickly.
EDIT: DAMN! And Destil beats me by 2 minutes! ::takes hat off:: It's all that math really.
